CJ 128-2007Heat meters (English PDF)

Foreword

The articles 4.2.2 4.2.4 4.2.5 4.3.2 4.3.3 and 5.1~5.12 in this Standard are compulsory

ones; the rest are recommendatory.

This Standard replaces CJ-128-2000 "Heat Meters", from the implementation date.

This Standard is the revision to CJ 128-2000 "Heat Meters". This revision references

to EU standard EN 1434-2007 "Heat meters". The major technical contents are

consistent with EN 1434; and it is consistent with JJG 225 "Verification Regulation of

heat Meters".

Compared with CJ 128-2000, the following aspects have been made to this Standard.

— Extend the flow-rate application scope of heat meter; add the requirements of

the heat meter with low flow-rate and large caliber;

— Add the requirements in installation length of heat meters;

— Add the requirements in pipe network water quality;

— Add the related requirements in cooling meter;

— Add Class C environmental requirement of heat meter;

— Add the requirements in data storage;

— Add the requirements in repetitiveness;

— Raise the requirements in electromagnetic compatibility;

— Raise the requirement in water temperature of exit-factory test; specify the

different water temperature conditions according to the type of heat meter in

type approval test;

— Delete the change size structural styles not used in China; make significant

amendment on installation drawing in the requirements in structure and

installation of platinum resistance temperature sensor;

— Add the technical requirements in photoelectric interface of heat meter;

— Add the requirements in the communication protocol used in heat meter data

transfer;

— Delete the technical contents in prepayment devices in Annex G in the former

standard.

Annex B, Annex C, Annex D, Annex E, Annex F and Annex G in this Standard are

normative; Annex A is informative.

Heat Meters

1 Scope

This Standard specifies terms and definitions, technical characteristic, requirement,

test method, test rules, marking, packing, and storage of heat meters.

This Standard is applicable to heat meters of which the flowing medium is water, the

temperature is 2°C~150°C, and the pressure is not larger than 2.5 MPa.

2 Normative References

The following normative documents contain provisions which, through reference in

this text, constitute that provisions of this Standard. For dated reference, the

subsequent amendments or revisions of these publications do not apply. Parties who

reach an agreement based on this Standard are encouraged to investigate the

possibility of applying the most recent editions of the standards indicated below. For

undated references, the latest edition of the normative document referred to applies.

GB 191 Packaging - Pictorial marking for handling of goods

GB/T 2423.1 Environmental testing - Part 2. Test methods - Tests A. Cold

GB/T 2423.2 Environmental testing - Part 2. Test methods - Tests A. Dry heat

GB/T 2423.3 Environmental testing - Part 2. Test methods - Tests A. Damp heat

Steady

GB/T 2423.4 Environmental testing for electric and electronic products - Part 2.

Test method - Test Db. Damp heat, cyclic (12h+12h cycle)

GB 4208-1993 Degrees of protection provided by enclosure (IP code)

GB 4706.1 Household and similar electrical appliances - Safety - Part 1. General

requirements

GB/T 9113.1 Integral steel pipe flanges with flat face or raised face

GB/T 17626.2 Electromagnetic compatibility (EMC) - Testing and measurement

techniques - Electrostatic discharge immunity test

GB/T 17626.3 Electromagnetic compatibility - Testing and measurement

techniques - Radiated radio-frequency electromagnetic field immunity test

GB/T 17626.4 Electromagnetic compatibility - Testing and measurement

techniques - Electrical fast transient/burst immunity test

GB/T 17626.5 Electromagnetic compatibility - Testing and measurement

techniques - Surge immunity test

GB/T 17626.8 Electromagnetic compatibility (EMC) - Part 4-8. Testing and

measurement techniques - Power frequency magnetic field immunity test

GB/T 17626.11 Electromagnetic compatibility - Testing and measurement

techniques - Voltage dips, short interruptions and voltage variations immunity tests

CJJ 34 Design code of district heating network

CJ/T 188-2004 Technical requirements of utility meters data transmission

JB/T 9329 Basic environmental conditions and testing methods for instruments

transportation and storage in the transportation

3 Terms and Definitions

The following terms and definitions apply to this Standard.

3.1

Heat meter

Meter that meters and displays the heat energy that the water-flow releases or

absorbs when passing heat exchange system.

3.2

Complete heat meter

Non-decomposable heat meter consisted of flow sensor, calculator and temperature

sensor pair.

3.3

Combined heat meter

Heat meter consisted of flow sensor, calculator and temperature sensor pair.

3.4

Cooling meter

Heat meter that meters the cooling amount in which the fluid medium temperature is

2°C~ 30°C and the temperature difference is not higher than 20K.

3.12

Maximum temperature difference

Upper limit value of a temperature difference, under which the accuracy of a heat

meter shall not exceed the error limit.

3.13

Flow-rate

Volume or mass of the heat carrier water that flows across a heat meter in unit time.

3.14

Minimum flow-rate

Lower limit of the flow-rate of water-flow that flows across a heat meter, under which

the accuracy of a heat meter shall not exceed the error limit.

3.15

The permanent flow-rate

Water flow-rate of a system under long-term normal continuous operation, under

which the accuracy of a heat meter shall not exceed the error limit.

3.16

Maximum flow-rate

Water extreme flow-rate of the water-flow that flows across a heat meter under normal

operation condition in a short time (1 h/d; < 200 h/a), under which the accuracy of a

heat meter shall not exceed the error limit.

3.17

Total volume

Total volume of water flowing across a heat meter.

3.18

The highest temperature

Maximum allowable temperature of water, when the accuracy of a heat meter does

not exceed the error limit.

3.19

The lowest temperature

Minimum allowable temperature of water, when the accuracy of a heat meter does not

exceed the error limit.

3.20

Maximum admissible working pressure

Maximum working pressure that a heat meter can bear with when it continuously

works under the highest temperature.

3.21

Pressure loss

Loss of pressure caused by a heat meter at specified flow-rate.

3.22

Admissible pressure loss

Limit of pressure loss of the water-flow that flows across a heat meter at permanent

flow-rate.

3.23

Maximum thermal power

Possible maximum value of thermal power when the accuracy of a heat meter does

not exceed the error limit.

4 Technical characteristics